1. Field of the Invention
The present invention relates to light fixtures, and particularly to sockets for engaging an outer end of a lamp mounted in a light fixture.
2. Description of the Prior Art
There has long been a need in the lighting industry for a lamp support to hold up the outer or non-electrical portion of a lamp in a lighting fixture. The advent of the extensive use of mercury, metal halide and high pressure sodium lamps, has further heightened this need. Such lamps come in very large sizes and their weight (when placed in a fixture to extend horizontally), causes them to lie at an angle so that they are not in proper focus. In operation, their relatively large size also causes them to vibrate to an early demise if unsupported. In addition, these lamp operate at temperatures of approximately 300.degree. C. (572.degree. F.) on the surface of the glass bulb of the lamp. Supporting such a lamp with a metal support or brace will cause the eventual decompositon of the glass because chemical interaction occurs at such high temperatures.
Certain materials have been used to coat that portion of a lamp support which engages the glass bulb, but with limited success. For example, molded teflon has been used, but this material has a melting point near 300.degree. C. (572.degree. F.) so there is very little margin of safety. Woven fiberglass sleeving has also been used, but this material eventually becomes frayed and then allows the metal support to contact the lamp bulb. Asbestos is no longer a viable option because its use is now restricted by law. In addition, none of these insulation materials provide any "cushion" to allow for expansion of the glass bulb as it becomes hot. Certain high energy lamps will continue to burn if their glass bulb is broken. If a lamp support is uncushioned, the glass bulb of a lamp can break upon expansion, with the lamp continuing to burn and thereby radiating harmful ultraviolet radiation.
Various attempts to support the outer portions of such high energy lamps are shown in U.S. Pat. No. 3,911,265, granted to Landrum et al. on Oct. 7, 1975, U.S. Pat. No. 3,781,539, granted to Landrum et al. on Dec. 25, 1973 and U.S. Pat. No. 3,610,915, granted to Moore on Oct. 5, 1971. The lamp fixture and support devices shown in these three patents are unsuitable for the reasons as stated above related to heat support and cushioning, as well as the fact that the support devices shown therein for the lamp bulbs take up excessive space inside of the lamp fixture reflector and hence cannot be used in fixtures where space is close between lamp and reflector. In addition, the outer end supports shown in these three patents are not shaped so as to fit different styles or types of lamps which may be installed in a particular lamp fixture. If a lamp with a different type outer portion or end is inserted in such lamp fixtures, it may necessarily require the changing of the type of lamp support, since its configuration may not be suitable for the different lamp. The present invention provides a lamp stabilizer for the outward portion of a high energy lamp which overcomes the disadvantages of the prior art.